Detailed Description   
2.5 Programming 
  Spindles (S1) 
2-64  Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0 
2.5.3  Programming of spindle controls via PLC with FC18 
Automatic gear step change with FC18 
When the PLC specifies the direction of rotation and speed using FC18, the NCK can 
determine and select a gear step to match the speed. This is equivalent to the M40 
functionality when programming via the part program. 
The correct start code must be set when FC18 is called in a PLC user program, in order to 
activate gear step selection. 
For detailed explanations on how to program spindle controls via the PLC with FC18, please 
refer to: 
References: 
/FB1/ Descriptions of Functions, Basic Machine; Basic PLC Program (P3) 
2.5.4  Special spindle motions via PLC interface 
Why use a special spindle interface?  
This function can be used to program the spindle via an axial PLC interface as an alternative 
to the FC18. The simplicity of the settings results in slightly restricted functionality. This 
functionality can be used preferably for simple control applications.  
Functionality 
Special VDI interface signals are provided to start and stop spindles outside a running part 
program. In this regard, the channel status and the program status need not be in the active 
mode. These states will occur, e.g., on RESET and in JOG mode. 
The spindle concerned must have the state "Channel axis" or "Neutral axis" and must not be 
moved using the JOG keys or positioned by FC18 or synchronized actions. If these 
conditions are fulfilled, spindle jobs will be accepted via the DBB30 spindle interface. 
The spindle settings are retained after a change in mode (e.g., from JOG mode to 
AUTOMATIC). The spindle settings (direction of rotation, speed or cutting rate) are applied 
to the part program at the start of the program and can be modified again using part-program 
instructions. In JOG mode, the spindle can be moved at the speed last programmed. 
Multichannel operation 
In the case of multi-channel operation, the spindle started by the PLC becomes active in the 
channel that handles the spindle at the appropriate moment.  
This channel can be determined on the PLC by reading NC/PLC IS: 
DB31, ... DBX68.0-68.3 (NC axis/spindle in channels A to D).